Valorization of cheese whey: closing the loop from protein extraction to whey protein film composting

Whey protein extracted from cheese-making by-products was analysed as a potential alternative for both food waste valorisation and food packaging waste reduction. Whey protein was ultrafiltered from local cheese whey and used for film manufacture via compression moulding. The physicochemical characterization of the extracted protein showed that the purity of the extracted protein was 91.6% wt. FTIR and XRD analyses, as well as SEM images, revealed the presence of lactose in the extracted protein. The solubility of the films made in water indicated that whey protein films would be suitable for packaging fatty foods, e.g. cheese, thus following the circular economy strategy. Furthermore, since the biodegradability of the films was higher than 70% after 48 h under composting conditions, it can be concluded that whey protein films are rapidly compostable in any industrial composting facility, highlighting the more sustainable character of these films. Finally, the environmental assessment confirmed that the film manufacturing process was the stage contributing the most to the environmental impact and, thus, this step should be optimised to reduce the environmental footprint of the films developed. Whey protein extracted from cheese-making by-products was analysed as a potential alternative for both food waste valorisation and food packaging waste reduction.